Bioroute Production Of Biodiesel Using Cerbera Odollam Oil In Packed Bed Reactor

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Date
2011-12
Authors
Rahman, Siti Norrahmah Ab
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Abstract
Diminishing reserves of fossil fuels and arising of food crisis recently have drawn attention for researchers to produce an alternative fuels. Biodiesel which is made from vegetable oils, animal fats or microbial oils is one of the attractive alternative fuels due to this concern. Other than that, biodiesel is an environmental friendly fuel which emitted less greenhouse effect gas. Cerbera odollam oil was determined as a non-edible feedstock for biodiesel production. The enzymatic transesterification of Cerbera odollam oil as a feedstock has been studied in the present research. Cerbera odollam oil has been extracted using n-hexane solvent in a soxhlet extractor. The enzymatic transesterification were carried out in a batch system to screen the most efficient enzyme among Lipozyme RM IM, Lipozyme TL IM and Novozyme 435 based on the highest fatty acid methyl ester (FAME) yield in the process. The best organic solvent used in this reaction was also determined in a batch process between tert-butanol and n-hexane to eliminate the inhibition of methanol in the reaction. Important parameters like temperature, speed agitation, enzyme concentration, methanol to oil ratio and solvent to oil ratio in enzymatic transesterification reaction were optimized by using response surface methodology (RSM) based on central composite design (CCD). The kinetic studies of enzymatic tansesterification were carried out in this research. Enzymatic transesterification of Cerbera odollam oil reaction was also studied in a packed bed reactor (PBR) for a continuous process. The effect of mass transfer in the PBR was also studied.54% of Cerbera odollam oil was extracted from the seeds. Lipozyme TL IM and tert-butanol were found as the suitable enzyme and organic solvent in this study. 67.05 % FAME yield was obtained using a combination of Lipozyme TL IM and tert butanol. The transesterification reaction of Cerbera odollam oil can reach up to 94.75 ± 2.43 % FAME yield with the optimized condition as suggested by RSM (R2=0.99) ; 4.1 w/w% enzyme based on oil weight, 1:5.1 oil to methanol molar ratio, 1:2 solvent to oil volume ratio, temperature of 45°C and 200 rpm agitation speed. By kinetics study of enzymatic transesterification of Cerbera odollam oil, a model based on Ping Pong Bi Bi with inhibition by methanol was found to fit the initial rate data and the kinetics parameters were evaluated by non-linear regression analysis. The maximum reaction rate, Vmax= 17.37 mmol/ml.min, Cerbera odollam oil binding constant, Km1=3.32 mmol/ml and methanol binding constant, Km2=3.00 mmol/ml were obtained. The Cerbera odollam oil transesterification in PBR can reach up to 86% FAME yield with 0.60 ml/min feed flow rate and 8 cm PBR height. In mass transfer study, models for FAME yield showed very good agreement between mass transfer model and the experimental data obtained from PBR operation, showing that in this study the FAME yield was mass transfer controlled (R2= 0.95). The high FAME yield in batch and continuous operation as well as the fuel characteristic meeting the standard of biodiesel proved that Cerbera odollam oil can be a promising feed stock for enzymatic transesterification process.
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Biodiesel fuels
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